RESUMEN
Background: Native to West Africa, Cola nitida is a tropical tree of about 8-12 in height that grows in lowland rainforest. This plant is best known in Africa for its seeds, used in phytotherapy but for their socio-cultural importance. Aims/Objective: This study investigated the antioxidant activity of condensed tannins of Cola nitida seeds by carrying out two antioxidant tests (DPPH and FRAP). Methods: From a hydro-ethanolic extract of Cola nitida seeds, two samples were made. One treated with casein (EC) and another one without treatment (EWC). The researsh of condensed tannins were carried out by precipitation with Stiasny reagent. The total polyphenol and tannin contents were evaluated by the Folin-Denis method and the antioxidant power by DPPH and FRAP tests. Results: Extract without treatment (EWC) showed more antioxidant activity than the extract treated with casein (EC). Thus, the IC50 of EWC which contains condensed tannins was 5.54±0.005 µg/ml, while that of EC (without condensed tannins) reached 61.92±0.165 µg/ml. Conclusion: Cola nitida seeds are rich in condensed tannins that play an important role in the antioxidant activity.
RESUMEN
Excessive free radicals in the body system are known to cause oxidative stress, resulting in some pathological conditions which are fast becoming a challenge that needs urgent attention. Plants are known to be good sources of antioxidants that have the potential of scavenging for free radicals in the body system. In a bid to find solution to the challenge of oxidative stress, three species of kolanut were analysed in this study for their antioxidant properties. The husk and testa of three species of kolanut (Cola acuminata, Cola nitida and Cola verticillata) were subjected to liquid and solid state fermentation for 10 days, after which it was dried, grounded and analysed. The effect of fermentation was checked quantitatively, comparing the antioxidant properties of the fermented and unfermented (control) samples. Radical scavenging ability (DPPH), Ferric Reducing Antioxidant Property (FRAP), Iron chelation, vitamin C, phenol and flavonoid were determined. The values obtained for the husk and testa of fermented and unfermented (control) samples were within the range of 0.210 to 1.17 mg/g for FRAP, 1.120 to 4.700 mg/g for phenol, 55.740 to 70.230% for DPPH, 0.263 to 1.577 mg/g for flavonoid, 88.410 to 97.733% for iron chelation, while that of vitamin C ranged between 1.913 to 4.633 mg/g respectively. The fermented samples had higher antioxidant properties for DPPH, phenol, Iron chelation and vitamin C than unfermented samples. This study has established the fact that the husk and testa of the kolanut species has antioxidant properties and thus can exert several beneficial effects by virtue of these properties.
RESUMEN
The seeds of Cola nitida were investigated for their anti-diabetic properties. The extracts were obtained by maceration in cold water. Alloxan was used to induce diabetes mellitus (DM) in the rats at 180mg/kg body weight and diabetes was confirmed after 48 hours. The Phytochemical analyses of the plants showed the presence of tannin, flavonoid, terpernoid, cardiac-gylcoside, and alkaloids. Anthraquinone and saponin were observed to be absent. Cola nitida was also observed to cause a reduction in blood glucose level from 599±0.667mg/dl (diabetic control) to 170±0.577mg/dl (extract treated group). The extract showed a significant (P<0.05) decrease of blood glucose level in alloxan induced diabetic rats. Cola nitida aqueous extract showed a higher level of potency when compared to a known anti-diabetic drug (Glanil).